The present disclosure relates to a vehicle fuel system, and particularly to a fuel vapor venting system associated with a vehicle fuel tank. More particularly, the present disclosure relates to a fuel vapor recovery canister included in a fuel vapor venting system.
Vehicle fuel systems are configured to vent pressurized or displaced fuel vapor from the vapor space in the fuel tank to a separate charcoal canister. The canister is designed to capture and store hydrocarbons entrained in fuel vapors that are displaced and generated in the fuel tank and then discharge filtered air from the canister to the atmosphere.
When a vehicle engine is running, a purge vacuum is applied to the charcoal canister via the engine intake manifold. Hydrocarbons stored (e.g., adsorbed) on charcoal held in the canister are entrained in a stream of atmospheric air drawn into the canister by the purge vacuum. This produces a stream of fuel vapor laden with reclaimed hydrocarbon material that is discharged through a purge hose into the intake manifold for combustion in the engine.
A large volume of fuel vapor is vented from the fuel tank into the canister during fuel tank refueling when the engine is off. A relatively smaller volume of fuel vapor is vented from the fuel tank into the canister when the engine is on and a purge vacuum is applied to the charcoal held in the canister to draw air from the atmosphere into the carbon bed.